Environmental Health — Flashcards

Flashcard 81: sewage is _____

Answer: liquid waste with faecal matter 

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Flashcard 82: Turbidity of water is measured in _____ units

Answer: nephelometric

Flashcard 83: Water is stored for _____ in the sedimentation tank of a rapid sand filter

Answer: 2-6 hours

Flashcard 84: The main disinfecting agent in chlorination is _____

Answer: Hypochlorous acid (HOCl)

Extra: Hypochlorous acid (HOCl) is the most effective disinfecting agent in chlorination. It is about 80-100 times more potent than the hypochlorite ion (OCl-). The dissociation of HOCl into OCl- depends on pH; at lower pH, HOCl predominates.

Flashcard 85: Water should be boiled for _____ for household purification.

Answer: 5-10 minutes

Flashcard 86: fresh fish has _____ gills

Answer: bright red

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Flashcard 87: Which wastes are not suitable for incineration?

Answer: - Pressurized containers - Reactive chemical waste - Silver salts and photographic waste - Halogenated plastics (e.g., PVC) - Waste with high heavy metal content (e.g., Mercury, Cadmium) - Sharps (metal)

Extra: Note: Incineration of PVC is prohibited as it leads to the release of toxic dioxins and furans.

Flashcard 88: heat production in composting is _____ degree celsius

Answer: >60

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Flashcard 89: heat stress index value ranges from _____

Answer: 0 to 100

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Flashcard 90: 2adcda56ad83444b9af9eff2bc7a4e93-ao-2

Answer: hardness of water

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